Restructure LKG dir so that GACing of 2.0.50726.900 runtime is no longer needed

closes #206

commit 2ef867e044e3a42b30ce5ad0971d006459e5c9b4
Author: latkin <latkin@microsoft.com>
Date:   Tue Feb 3 15:15:46 2015 -0800

    Remove GACing from appveyor build

commit af79f865062d8144de1a734787e92cd50a383450
Author: latkin <latkin@microsoft.com>
Date:   Tue Feb 3 13:50:41 2015 -0800

    Restructure LKG dir so that GACing of 2.0.50726.900 runtime is no longer needed

Conflicts:
	DEVGUIDE.md

DEVGUIDE.md

@@ -27,10 +27,7 @@ See the script for what this does.  After you do this, you can do further testin
 The compiler is compiled as a set of .NET 4.0 components using a bootstrap process. This uses the Last Known Good (LKG) compiler to build.  
 Note that you need the .NET framework 3.5 installed on your machine in order to complete this step.
 
-```
-gacutil /i lkg\FSharp-2.0.50726.900\bin\FSharp.Core.dll
-msbuild src\fsharp-proto-build.proj
-```
+    msbuild src\fsharp-proto-build.proj
     
 ## 2.  Building an F# (Debug) library and compiler
 

appveyor-build.cmd

@@ -7,9 +7,6 @@ set _msbuildexe="%ProgramFiles(x86)%\MSBuild\12.0\Bin\MSBuild.exe"
 if not exist %_msbuildexe% set _msbuildexe="%ProgramFiles%\MSBuild\12.0\Bin\MSBuild.exe"
 if not exist %_msbuildexe% echo Error: Could not find MSBuild.exe.  Please see http://www.microsoft.com/en-us/download/details.aspx?id=40760. && goto :eof
 
-set _gacutilexe="%ProgramFiles(x86)%\Microsoft SDKs\Windows\v8.1A\bin\NETFX 4.5.1 Tools\gacutil.exe"
-if not exist %_gacutilexe% echo Error: Could not find gacutil.exe.  && goto :eof
-
 set _ngenexe="%SystemRoot%\Microsoft.NET\Framework\v4.0.30319\ngen.exe"
 if not exist %_ngenexe% echo Error: Could not find ngen.exe. && goto :eof
 
@@ -17,9 +14,6 @@ if not exist %_ngenexe% echo Error: Could not find ngen.exe. && goto :eof
 @if ERRORLEVEL 1 echo Error: Nuget restore failed  && goto :eof
 
 ::Build
-%_gacutilexe%  /i lkg\FSharp-2.0.50726.900\bin\FSharp.Core.dll
-@if ERRORLEVEL 1 echo Error: gacutil failed && goto :eof
-
 %_msbuildexe% src\fsharp-proto-build.proj
 @if ERRORLEVEL 1 echo Error: compiler proto build failed && goto :eof
 

lkg/FSharp-4.0.30319.1/bin/FSharp.Core/README.txt

@@ -0,0 +1,3 @@
+The copy of FSharp.Core in this directory is version 2.0.50726.900, required by FSharp.SRGen.Build.Tasks.dll and other legacy Power Pack libraries in the parent directory.
+
+This copy of FSharp.Core.dll should not be referenced as an LKG, it is present merely as a workaround to enable the legacy libraries to work without needing to update the GAC.